The LWF Blog
Fire Safety Engineering for Design – Foam Fire Suppression Systems – Part 282
April 13, 2026 9:05 amLWF’s Fire Safety Engineering blog series is written for Architects, building designers and others in the construction industry to highlight and promote discussion on all topics around fire engineering. In part 281, LWF talked about water sprinklers and sprayers. In part 282, we will discuss branch pipes and monitors (foam cannons).
Foam branch pipes and monitors (sometimes referred to as foam cannons) are firefighting devices capable of projecting firefighting foam over a long distance. A branch pipe is usually a portable nozzle which is attached to a hose for use by firefighters. A foam monitor is a fixed or semi-fixed nozzle mounted on platforms, vehicles, trailers or remotely-controlled/manual turrets.
Water, foam concentrate and air is mixed to produce an aspirated foam which is discharged as a jet or stream capable of travelling significant distances horizontally or vertically. A large monitor is able to deliver very high flow rates, typically up to around 60,000 litres per minute or even more in some setups.
Should the jet or stream of foam be jetted or plunged into the fuel of a fire, the effectiveness will be reduced, due to the breaking of the fuel surface. The foam can mix with the burning liquid rather than forming a gentle, continuous blanket on the surface.
Foam branch pipes and monitors should not be used with polar solvents, such as ethanol, methanol or acetone. One reason is that high energy application from the monitors can disturb the fuel surface. In addition, polar solvents are capable of breaking down regular foam and fires involving a polar solvent should be dealt with using foam pourers, deflectors and a slow build-up of the foam layer.
Foam branch pipes and monitors are best used where large-scale flammable liquid hazards are present. For example, they are often employed to protect storage tanks such as oil tanks, fuel depots or chemical storage; bunds and containment areas; process and handling areas such as refineries, petrochemical plants; and aircraft hangars and helicopter decks.
Foam monitors are powerful tools in fire protection and critical for managing fires over large areas, but should be avoided for delicate fuel surfaces or polar solvent fires.
In part 283 of LWF’s series on fire engineering we will discuss foam inlet (semi-fixed) systems. In the meantime, if you have any questions about this blog, or wish to discuss your own project with one of our fire engineers, please contact us.
Lawrence Webster Forrest has been working with their clients since 1986 to produce innovative and exciting building projects. If you would like further information on how LWF and fire strategies could assist you, please contact the LWF office on 0800 410 1130.
While care has been taken to ensure that information contained in LWF’s publications is true and correct at the time of publication, changes in circumstances after the time of publication may impact on the accuracy of this information.